#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#include<string.h>
void replace(char*arr)
{
	int left = 0;
	int right = strlen(arr) - 1;
	while (left <= right)
	{
		char temp = arr[left];
		arr[left] = arr[right];
		arr[right] = temp;
		left++;
		right--;
	}
}

int main()
{
	char arr[] = "abcdef";
	replace(arr);
	printf("%s", arr);
	return 0;
}